1. Epithelial odontogenic tumors

2. Calcifying epithelial odontogenic tumor Pindborg tumor

3. Definition
A locally invasive epithelial odontogenic neoplasm characterized by development of intra-epithelial structures ( of amyloid-like nature), which become calcified and liberated when the cell break down.

4. The tumor cells bear a close morphologic resemblance to the cells of the stratum intermedium of the enamel organ.
recently suggested that the tumor arises from dental lamina

5. Clinical features
Pindborg was the first who described it as a separate entity.
It is slowly growing painless lesion.
Relative frequency:
Age: Wide age range (20-60 years).

6. Site: Mandible 2:1 Premolar-molar area.
Peripheral type affect anterior region.
Sex: no predilection.

7. X-ray Unilocular radiolucency ( common pattern).
Multilocular radiolucency, less common.
Associated with unerupted tooth.
Foci of calcification.

9. Histopathology
Sheets of polyhedral epithelial cells with distinct outlines and intercellular bridges, large hyperchromatic nuclei, prominent nucleoli, and pleomorphism.
Amorphous eosinophilic hyaline material (amyloid-positive), calcification of these materials called Liesegang rings.
Basophilic calcification within connective tissue stroma.

12. Treatment Conservative resection with narrow rim of bone.
Recurrence rate is 15%.

13. Squamous odontogenic tumor

14. Definition
It is locally infiltrative epithelial odontogenic neoplasm consisting of islands of well differentiated squamous epithelium in a fibrous stroma.

15. Clinical faetures
Pullon and colleagues proposed the first description of these lesions as specific entity in 1975.
Origin:
The squamous odontogenic tumor may arise from neoplastic transformation of dental lamina rests
Rests of Malassez the tumor appears to originate within the periodontal ligament that is associated with the lateral root surface of an erupted tooth.
Age:
2nd to 7th decades, Mean age 38 years.

16. Site: Both jaws.
Multiple lesions ( hamartomatous).
Sex: no predilection.

18. Histopathology
It is consisting of islands of well differentiated squamous epithelium in a fibrous stroma.
Presence of calcification within epithelial islands.
Hyalinization of fibrous connective tissues.

21. X-ray
Triangular radiolucency lateral to the root.

23. Treatment
Conservative excision.
No recurrence.